Method for driving display device
View Patent ↗An object is to provide a convenient display device which consumes sufficiently small amount of power and a method for driving such a display device. The display device can be in an off state with a still image displayed in a still image display mode in which a pixel electrode and a common electrode which are for applying a voltage to the display element are brought into a floating state so that a voltage applied to the display element is held, and a still image is displayed without further supply of a potential. The display device is put to an off state with a desired image displayed in the still image display mode, whereby the display device can have a higher level of security and can be more convenient.
1. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source;
writing an initialization image signal to the display device;
displaying an initialization image on the screen in the still image display mode;
stopping supply of the power supply potential with the initialization image displayed on the screen;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the initialization image at the same time,
wherein supplying the power supply potential is controlled by a transistor comprising an oxide semiconductor in a channel formation region.
2. The method for driving a display device, according to claim 1 , wherein a period of time in which the initialization image is displayed after supply of the power supply potential is stopped is set by controlling a period of time in which the light source is driven.
3. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source;
supplying a retention and stop signal to the display device;
stopping supply of the power supply potential with the image displayed on the screen in the still image display mode;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the image at the same time,
wherein supplying the power supply potential is controlled by a transistor comprising an oxide semiconductor in a channel formation region.
4. The method for driving a display device, according to claim 3 , wherein a period of time in which the image is displayed after supply of the power supply potential is stopped is set by controlling a period of time in which the light source is driven.
5. The method for driving a display device, according to claim 3 , wherein supply of the power supply potential is stopped after writing an image signal of one frame is finished.
6. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source and applying a voltage to a display element;
writing an initialization image signal to the display device;
displaying an initialization image on the screen in the still image display mode;
stopping supply of the power supply potential while the initialization image is displayed on the screen by application of the voltage to the display element;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the initialization image at the same time,
wherein supplying the power supply potential is controlled by a transistor comprising an oxide semiconductor in a channel formation region.
7. The method for driving a display device, according to claim 6 , wherein a period of time in which the initialization image is displayed after supply of the power supply potential is stopped is set by controlling a period of time in which the light source is driven.
8. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source and applying a voltage to a display element;
supplying a retention and stop signal to the display device;
stopping supply of the power supply potential while the image is displayed on the screen in the still image display mode by application of the voltage to the display element;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the image at the same time,
wherein supplying the power supply potential is controlled by a transistor comprising an oxide semiconductor in a channel formation region.
9. The method for driving a display device, according to claim 8 , wherein a period of time in which the image is displayed after supply of the power supply potential is stopped is set by controlling a period of time in which the light source is driven.
10. The method for driving a display device, according to claim 8 , wherein supply of the power supply potential is stopped after writing an image signal of one frame is finished.
11. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source through a transistor and applying a voltage to a display element;
writing an initialization image signal to the display device;
displaying an initialization image on the screen in the still image display mode;
turning off the transistor to bring the display element into a floating state while the initialization image is displayed on the screen by holding of the voltage applied to the display element;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the initialization image at the same time,
wherein the transistor comprises an oxide semiconductor in a channel formation region.
12. The method for driving a display device, according to claim 11 , wherein a period of time in which the initialization image is displayed after the transistor is turned off is set by controlling a period of time in which the light source is driven.
13. A method for driving a display device, comprising:
determining whether a mode of driving the display device is a moving image display mode or a still image display mode by a comparator circuit;
displaying an image on a screen by supplying a power supply potential from a power source through a transistor and applying a voltage to a display element;
supplying a retention and stop signal to the display device;
turning off the transistor to bring the display element into a floating state while the image is displayed on the screen in the still image display mode by holding of the voltage applied to the display element;
driving a light source for a predetermined time after the step of stopping supply of the power supply potential; and
stopping driving the light source and stopping displaying the image at the same time,
wherein the transistor comprises an oxide semiconductor in a channel formation region.
14. The method for driving a display device, according to claim 13 , wherein a period of time in which the image is displayed after the transistor is turned off is set by controlling a period of time in which the light source is driven.
15. The method for driving a display device, according to claim 13 , wherein supply of the power supply potential is stopped after writing an image signal of one frame is finished.